Laminated bowling pin



K. KBA'FT LAMINATED BOWLING PIN Filed Feb. 10, 1939 FEZ RA RL KRAFT /4 7" TPNEV Petenieu June 11, 1941 UNITED sTATEs PATENT OFFICE LAMINATED BOWLING PIN Karl Kraft, Chicago, Ill.

Application February 1o. 1m. serai Nn. zsassz 1 calm. (c1. ziaazi is to provide a bowling pin, the weight of which can be adjusted and controlled within rather small limits, thereby providing a distinct advantage over pins made from solid billets of wood. the weights of which, of course, depend entirely upon the particular wood inasmuch as the standard bowling pins are all of the same size while the wood itself may vary considerably so far as specinc gravity ls concerned.

An important object of the invention is the provision of a bowling pin which has a further advantage over the usual solid pin in that it possesses an unusual amount of springiness and liveliness while, at the same time, retaining the desired ring which is inherent in good bowling pins and which is demanded by good bowlers.

A still further important object is to provide a bowling pin which, on account of its laminated construction, can be made of even more selected woods than the usual solid pin and which also. on account of the specialtype of laminations and the cementing process. will not be any more liable to splitting, chipping, cracking or breaking than the ordinary solid pin.

Other and further important objects of the invention will be apparent from the disclosures in the accompanying drawing and following specification. 1

The invention, in a preferred form, is illustrated in the drawing and hereinafter more fully described.

In the drawing:

Figure 1 is a side elevation of the pin of this invention, showing' the laminations and also showing the weight control openings in dotted es. ligure 2 is a vertical section of the pin of Figure 1.

Figure 3 is another side elevation of the bowling pin o f this invention with the outer laminated slab removed 4and showing the interior construction.

Figure 4 is a sectional view taken on the line 4--4 of Figure 1.

As shown in the drawing:

The reference numeral Il indicates generally a bowling pin composed of a 'number of laminated slabs of wood I2, il, I6, and i8, preferably maple. 'I'he wood in the trunk of a tree is classi.. fied into several categories by expert woodsmen, the particular classifications being heart, sap, and bark wood. It is an acknowledged fact that the heart and bark portions of a piece of lumber will tend to chip and crack more readily than the sap wood, and it is, therefore, the intention of this inventor to use sap wood or other choice material for all the laminated slabs of this pin when this is convenient. However. it is not necessary to use sap wood to produce this pin as both the heart and bark portions will serve satisfactorily as proven by experimentation.

'Ihe slabs oi wood I2, il, I8 and i8 are joined by means of a casein glue or the like which is strong enough to hold the pieces together under any amount of shock the pin may receive. The two central slabs I4 and l0 are glued first, and openings of any size or shape are cut or drilled in the lower portion of this combination which is to form the body of the pin. As shown, the holes 20 and 22 are drilled completely through the glued slabs il and I8. 'Ihese cavities in'the central portion of the finished pin make for a lighter and livelier bowling pin. It is possible to make these holes any size and, therefore, the weight of the pin can be controlled within almost any desired limits. The slabs of wood are each weighed before any further laminating is done, and the size of each hole is regulated by the weight of the slabs to be assembled for one pin. It is possible under these pre-arranged calculations to produce pins that will not vary in weight by more than approximately one ounce. Heretofore, solid wood bowling pins have sometimes varied from one to twelve ounces in weight even in individual sets of ten.

Obviously, solid maple bowling pins are quite expensive to manufacture. `It is necessary to allow the blocks of wood cut out for pins to age or dry out for a considerable time, and expensive kiln drying is also employed. This requires a large investment of capital in the preliminarily shaped billets and a considerable supply must always be kept on hand. Thus, the price of bowling pins are increased to make up for the drying period of the pins or the period in which the invested capital is idle.

Kiln drying of pins has not been uniformly successful. The sudden or even slower forced drying of such a thick piece of wood such as needed to make a solid pin tends to close up the outer pores, and hence, seal moisture in the centrai portion of the nnished pin, checking and cracki results. By the time pins ofthis nature are put on the market, the weight of each pin is dinerent. and the condition o! the pins have often changed materially. Further difilculties are also caused by warping due to the eliminate checking and cracking to a marked sealed moisture sometimes left in the undried center of the Din. t

The laminated and hollow central portion of the pin of this invention does away with all of these diiiiculties encountered in a regular solid bowling pin.

The slabs of wood I2, Il, Il and I8 usedfor laminating are thin enough to be quickly kiln dried, thus eliminating the longer drying period. The holes Il and 22 drilled in the center of the pin make it possible to regulate very closely the iinal weight of the pin. Solid pins have the disadvantage of having three or more classiilcations of wood in one pin and this disadvantage relates more particularly to the heart and bark portions on opposite external sides of the pin. When the pins check or crack, it is generally on one of these two surfaces. By doing away with all heart and bark wood in the manufacture of bowling pins as is possible with this new pin, it will degree.

The'bowling pin of this invention can be manufactured much more economically than can a solid pin. This new pin has been proven to be more desirable, to have more life and to be more advantageous in many ways' than any pin previously made.

v I am aware that many changes may be made and numerous details of 'construction varied v throughout a wide range without departing from the spirit of the invention, and I. therefore, do not purpose limiting the patent granted hereon otherwise than as necessitated by the prior art,

I claim as my invention:

A laminated bowling pin composed of four slabs of sap-wood maple, a waterproof glue between each two slabs, the two central laminations each having at least two holes in the lower portions thereof, the size and location of the holes to be determined by a preliminary calculation of the possible final pin weight, whereby a balanced pin for balanced sets of ten-pins and one with a harder wearing surface throughout results.

KARL KRAFT. 

